Gearing.



K. ALQUIST.

GEARING.

APPLICATION FILED JULY 3, 1915.

Patented Dec. 28, 1915.

Inventor:

Karl. J LUiSb,

KARL ALQUIST, OF SCHENECTADY, NEW YORK.

GEARING.

rieasao.

Specification of Letters Patent.

Patented Dec. 2%, M7315.

Application filed July 3, 1915. Serial No. 37,979.

To all whom z'tmay concern:

Be it known that I, KARL AL UIsT, a subjeot of" the King of Sweden,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Gearing, of which thefollowing is a specification.

The present invention relates to power transmission by means of spurgearing and is a continuation in part of my application Serial No.758,825, filed April 4', 1913, an Serial No. 812,812, filed January 17.,1914.

The invention is applicable to gearing for either speed reduction ormultiplication, but the more general field is for speed reduction and asa matter of convenience the invention is described in connection withreduction gearing, but it will be understood that it is not necessarilylimited thereto.

The invention relates more particularly to high speed gearing intendedto transmit large loads with relatively great speed re duction, and maybe embodied in connection with single reduction gearing, or double, orgreater reduction gearing. It comprises the introduction between thedriving and driven gear-wheels of two elastic or flexible gear-wheelsarranged in parallel relation to each other and through which the loadis transmitted. in the case of single reduction gearing they areintroduced directly between the driving and driven elements, while inthe case of double or greater reduction they are introduced at asuitable point in the train of gearing, as will appear more fullyhereinafter.

In power transmission by means of spur gearing of any considerable powerand speed reduction. it is, of course, desirable'and advantageous to usesingle reduction gearing when possible, as it is simpler to construct,but in actual practice there issoon reached a limit beyond which theordinary single reduction type is unsatisfactory and more expensive toconstruct, and it becomes necessary to resort to a double reduction. Onthe one hand there is in most cases a limit to the size of the drivengear-wheel determined by .pinion diameter decreases.

be transmitted. The power that can be transmitted per unit length ofpinion, or-

width of face, decreases very rapidly as the The mean radius ofcurvature of the load carrying tooth surface is a linear function of thepinion diameter, and it is known that the load carrying capacity of acurved surface varies with its radius of curvature. Furthermore,

when the pinion diameter is decreased the pitch line velocity is,generally-speaking, also decreased, and the power that may betransmitted by the pinion will thus vary at least with the second powerof the pinion diameter. Other influences greatly complicate the questionand the horse-power that can be transmitted may be said to be for agear-Wheels, thus adding to their cost of' manufacture and Weight, andany way the limit to the possible length of the pinion is quicklyreached owing to the bending and the deflection or twisting action whichtakes place in a pinion of small diameter and the difiiculty ofproviding sufficient bearing surface for it.

By my invention wherein two intermediate elastic gears operating inparallel are provided to transmit the power from the driving to thedriven shaft, I am enabled to decrease the length of the pinion byonehalf fora certainpower to be transmitted. This is photo the fact thatin view of the elasticity of the intermediate gear-wheels it is insuredthat at all times the load is equally divided between them. Further, Iarrange the pinion shaft directly in line with the shafts which carrythe intermediate gear-wheels, and with the pinion thus balanced betweenthe. intermediate elastic elements, the pinion bearings receive no partof the driving thrusts as the thrusts will be transmittedto and taken upby the bearings of the intermediate gear-wheels. This is of greatadvantage in that it is much easier to provide substantial bearings forthese intermediates than for the pinion. The pinion also is not subjectto bending strains, and any torsional deflections or imperfections inthe gear teeth will be taken care of by the elastic elements.

From the above it will be seen -that I am enabled by my invention totransmit a larger load per unit length of pinion at a given speedreduction with a single reduction gearing; and that when a doublereduction gearing is found to be desirable the invention also enablesthe use of a shorter length of pinion, which means a smaller gearingthroughout and one which will be more compact and cheaper tomanufacture.

Referring to the accompanying drawings, Figure 1 is a plan view of asingle reduction gearing embodying my invention and is here shown, byway of example, as connecting a steam turbine to an electric generator;Fig. 2 is a diagrammatic elevation of the gearing shown in Fig. 1; Fig.3 is a similar elevation showing an arrangement wherein two pinions areeach connected through parallel elastic elements to a single largegear-wheel; F ig. 4 is a similar view showing a single pinion connectedthrough two elastic elements to two large gear-wheels; Fig. 5 is asectional elevation illustrating a preferred form of elastic gear-wheel;and Fig. 6 is an elevation showing my invention as applied to doublereduction gearing.

Referring to the drawing, Figs. 1 and 2. 12 indicates a steamturbine-having its shaft 13 journaled in bearing blocks 14 and 15 andfixed thereon between the blocks is a solid pinion 16. The bearingblocks also have journaled therein two counter shafts 17, one above andone below the shaft 13,-

each of which carries a flexible or elastic gear-wheel 18, and both ofthese elastic gear-wheels mesh with the large driven gear wheel 19 fixedon the shaft 20 of the electric generator 21. It will be apparent thatthe elastic gear-wheels 18 in this arrangement are idlers, since theyneither increasenor reduce the ratio existlng' between p1I110I1 16 andgear 19. In the present instance the pinion 16 and wheels 18 are shownlocated. at one side of-the wheel 19, but it will be understood thatthey may be located either above or below it as found desirable. Thepinion shaft 13 is directly in line with shafts 17, thus balancing thepinion 16 between the flexible wheels 18. It is desirable to haveperfect alinement of these shafts, as the degree to which the pinion isbalanced depends upon this.

In gearing of this type the double helical or herring-bone type ofgearing possesses well recognized advantages as to smoothness of runningand other qualities, and I have accordingly illustrated my invention inconnection with such gearing. .In this case I prefer to use for myelastic element the form 22 rigidlymounted on the shaft or support andhaving a small clearance space between each two plates near theperiphery. The face of the gear-wheel is provided with helically cutteeth which are free to yield laterally by a slight amount under thepressure of the teeth of the cooperating gear-wheels. This yielding ofthe teeth is due to the fact that the metal plates are elastic and alsoto "the fact that each plate at its periphery is separated from theother by a small space.

In Fig. 3 I have shown my invention in connection with a double sideddrive, which gives a maximum power transmission for a.

minimum weight. I then prefer to use on each side of the driven wheel 19two flexible or elastic gear-wheels 18*, each pair driven by a pinion16*. Where it is desired to drive two large wheels 19 from a singlepinion 16 I employ the arrangement shown in Fig. 4 in which twointermediate flexible or elastic wheels 18 transmit the power-from thlatter to the former.

In Fig. 6 I have shown myinvention in connection with double reductiongearing.

In this arrangement 25 indicates the driving pinion driving the twointermediate elastic gear-wheels 26 fixed on the same shaft with whichare intermediate or low speed pinions 28 which mesh with the drivenwheel 29.

The elastic wheels 26 are preferably of the type referred to above andin this arrangement, although their functions are the same, they are notidlers as in the case of single reduction gearing but they form a partofthe speed reduction train.

My invention as applied to double reduction gearing is not specificallyclaimed herein as it forms the subject matter of another application,Serial No. 36,961, filed June 29, 1915.

In accordance with the provisions of the patent statutes, I havedescribed the-principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof;but I desire'to have it understood'that the. apparatus shown is onlyillustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. In a transmission gearing, the'conibination of a driving gear-wheel,a driven gear-Wheel, and two intermediate elastic gear-wheels, both ofwhich are peripherally in mesh with and directly transmit power from thedriving to the driven gear-wheel.

2. In a transmission gearing, the combination of a helical drivinggear-wheel, a

the same plane, and two intermediate elastic helical driven gearswheel,both located in gear-wheels, both of which meshwithand directly transmitpower from the driving to the driven gear-wheel.

3. In a transmissiongearing, the combination of a helical drivinggear-wheel, a

helical driven gear-wheel, both located in gear-wheel which meshes withboth of said elastic gear-wheels.

5. In a transmission gearing, the combinationof a pair of helicaldriving gear-wheels having teeth with right and left hand pitch, ahelical driven gear-wheel, and four intermediate gear-wheels havingelastic teeth which directly transmit power and mesh with said drivingand driven gear-wheels.

6. In a transmission gearing, the combination of a rigid pinion,two-elastic gearwheels which receive power from the pinion and arein-mesh therewith at substantially diametrically opposite points, and arigid driven gear-wheel which meshes with and is driven by both of saidelastic gear-wheels.

7. In a transmission gearing, the combination of a driving gear-wheeh'adriven gear-wheel, and two intermediate gearwheels which are arrangedbetween the driving and driven gear-wheels and transmit power from theone to the other, said intermediate gear-wheels having elastic teeth.

8. In a transmission gearing, the combir nation of a driving gear-wheel,a driven gear-wheel, and two intermediate elastic gear-wheels, both ofwhich transmit power from the driving'to the driven gear-wheel, saidelastic gear-wheels comprising a plurality of plates securely boundtogether at their central portions and with their outer portions unboundand slightly spaced apart so as to be free to yield at right angles tothe planes of the plates.

9. In a transmission gearing, the combi nation of a helical drivinggear-wheel, a helical driven gear-wheel, both located in the same plane,and two elastic gear-wheels that transmit powerffrom the driving to thedriven gear-Wheel, each of said elastic gear-wheels comprising aplurality of plates KARL ALQUIST.

